循环利用重组大肠杆菌细胞转化合成丁二酸

Reuse of recombinant Escherichia coli to produce succinic acid by bioconversion

研究了回收丁二酸发酵液中的大肠杆菌进行细胞转化的可行性,以转化率和生产效率为指标,考察了不同菌体浓度、底物浓度、pH调节剂对细胞转化的影响。发酵结果表明大肠杆菌可以在仅含有葡萄糖和pH调节剂的水环境中转化生产丁二酸,并确定了最佳的转化条件为:细胞浓度(OD600)50,底物浓度40g/L,缓冲盐为MgCO3。基于优化好的条件,在7L发酵罐中进行重复批次转化,第1次转化的转化率和生产效率分别达到91%和3.22g/(L·h),第2次转化的生产效率和转化率达到了86%和2.04g/(L·h),第3次转化的转化率和生产效率分别达到了83%和1.82g/(L·h)。

The possibility of reusing Escherichia coli cells from the broth for succinic acid production was investigated.Using succinic acid yield and productivity as criterion,we investigated the effects of cell concentration,initial glucose concentration,different neutralizers on the bioconversion.The results revealed that E.coli could convert glucose to succinic acid in a water solution of glucose and a neutralizer.According to the results,the optimal condition was as follows：the cell concentration was 50（OD600）,glucose concentration was 40 g/L and neutralizer was MgCO3.Under the optimum conditions,we carried out the consecutive batch bioconversion in 7 L fermenter.Succinic acid yield reached 91% with the productivity of 3.22 g/（L·h） for the first conversion.For the second conversion,succinic acid yield reached 86% with productivity of 2.04 g/（L·h）.Furthermore,we achieved a high mass yield above 83% with the productivity of 1.82 g/（L·h） for the third bioconversion.